Question

Which one is not a coenzyme?

• A. NAD${}^{+}$
• B. NADP
• C. FAD
• D. ATP

Answer 1

The correct option is D ATP

Coenzymes are non protein organic molecules which assist the enzymes to catalyse the biochemical reactions. They are generally derived from water soluble vitamin B complex. For example NAD and NADP both derived from niacin act as coenzymes with enzymes of electron transport chain to facilitate the transfer of electron from substrate to products. Similarly, FAD acts as coenzyme for photolyase enzyme which catalyses the breakage of UV induced thymine dimers. Here ATP is not a coenzyme as it doesn't have any property to facilitate an enzyme catalysed reaction. It can be an allosteric modulator, a signalling molecule, a product or a substrate for an enzyme but not a coenzyme.

So, the correct answer is 'ATP'.